Capsulated fuel injection nozzle



Oct. 22, 1968 F. J. CLAFFEY CAPSULATED FUEL INJECTION NOZZLE Filed May9, 1966 INVENTORI FRANK J. C LAFFEY WWW ATTYS United States PatentABSTRACT OF THE DISCLOSURE A capsulated nozzle for fuel injection nozzleassemblies comprising a cylindrical body portion, an elongated shank ofreduced cross section projecting from one axial end of the body portionterminaitng at its free end in a nozzle tip having at least onedischarge orifice therein. The body portion has an enlarged upper axialbore defining a spring chamber and a second lower axial bore having alower en-. larged portion in the shank defining a. fuel chamber. A valvemember having a nozzle is mounted in the second axial bore which in theclosed position seats against an inner conical seat in the nozzle tipportion. A valve actuator assembly normally maintains the valve memberin a closed position and includes a compression spring disposed betweenan upper and lower spring seat and a valve lift stop member forpreloading said compression spring and determining the valve lift. Thevalve lift stop member is detachably secured to the body portion of thenozzle by means of a bar-like head portion engageable in a groove in aWall of the spring chamber and has a rod depending from the head portionspaced from the inner terminal end of the valve member in the closedposition to determine valve lift.

The present invention relates'to fuel injection nozzles for internalcombustion engines. More particularly, the present invention relates toa compact, unitized capsulated fuel injection nozzle assembly. I

Conventional fuel injection nozzle assemblies generally comprise anelongated holder and a nozzle mounted at one end of the holder by meansof a cap nut. The nozzle usually consists of a generally cylindricalbody portion and an elongated shank of reduced cross section dependingfrom the body portion and a valve member mounted in an axial boreextending lengthwise of the nozzle. The valve is normally biased to aposition closing the spray orifices in the free end of the nozzle tip bymeans of a biasing spring. In some of these assemblies an elongatedgenerally cylindrical valve stop spacer is mounted between the holderand the nozzle by means of the cap nut. The valve stop spacer has anaxial chamber therein in which is mounted the biasing spring for thevalve element of the valve nozzle. The biasing spring assembly includesa lower spring seat, an upper spring seat and pressure adjusting shimsbetween the upper seat and the lower axial end face of the holder. Theseshims are used to provide the necessary adjustment for setting the biasof the spring for the valve element to adjust or set opening pressure ofthe valve.

These conventional assemblies are comparatively eX- pensive tomanufacture because of the plurality of parts valve. Moreover, theconfronting mating surfaces of the holder, valve stop spacer and nozzlemust be lap finished which, of course, is a machining operation whichadds to the expense of the overall assembly. Even if these matingsurfaces are highly machined, there is still the danger of leakage inthe fuel injection nozzle assembly.

In view of the above, the present invention is designed to provide amore simplified fuel injection nozzle assembly which is easy andeconoimcal to make and assemble and which provides several functionaladvantages over the prior assemblies discussed above.

In accordance with the present invention, the nozzle is attacheddirectly to the holder and includes an axial bore in the body portiondefining a spring chamber. The biasing assembly for the valve elementincludes a lower spring seat having a spherical surface against whichthe spherical inner terminal end of the valve seats, somewhat in thenature of a ball and socket arrangement, an upper spring seat alsohaving a spherical surface within which a valve spring spacer seats. Theparts such as the biasing spring, and spring seats are easily assembledin the spring chamber and are retained in assembled relation by means ofa valve lift stop element having a head portion detachably secured tothe valve body portion and a depending rod disposed centrally of thespring and spaced a predetermined distance from the upper end of thevalve to set the valve lift. This arrangement provides a more compactunit and eliminates the number of mating flat surfaces of conventionalnozzle assemblies discussed above. The unit is more compact by reason ofthe fact that all of the actuating elements for the valve are containedin the nozzle and may be pre-assembled to provide the desired valve liftand spring biasing force prior to assembly to the holder. Thus, theentire assembly is much easier to install initially and the nozzle ismuch simpler to replace when necessary. Furthermore, in the presentinstance a separate spray tip insert is provided in the nozzle tipwhereby the angular fuel passage in the nozzle may be drilled from thenozzle tip end which greatly simplifies formation of the fuel passagewayin the nozzle assembly. Additionally, side thrust on the valve isminimized by providing spherical seats on the upper and lower springwhich have to be precision made. Further, the elements of the assemblyhave to be installed in a proper sequence and thus they are difficultand time consuming to assemble properly. Notwithstanding the above, itis extremely difficult to accurately set the spring to provide thedesired biasing force for proper operation of the valve member and toaccurately assemble the parts to provide the desired valve lift.Additionally, it has been found that in these assemblies there is acertain amount of side thrust on the valve member which tends tointroduce valve sticking and in some cases effects normal operation ofthe guide elements and a mating spherical contact surface on the valveelement. It has also been found that in this assembly the spring ratemay be adjusted much more simply.

With the foregoing in mind, an object of the present invention is toprovide a fuel injection nozzle assembly which is of comparativelysimplified construction so that it is easy to manufacture and assemble.

A further object of the present invention is to provide a fuel injectionnozzle assembly characterized by novel features of construction andarrangement whereby the side thrust on the valve element is minimizedand the spring setting for biasing the valve element may be setprecisely before assembly of the nozzle to the holder.

Still another object of the present invention is to provide a capsulizedcomparatively compact nozzle unit which houses the biasing assembly forthe valve element which may be readily assembled and disassembled to theholder for ease of installation and replacement when necessary.

These and other objects of the present invention and the variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawing, wherein:

FIG. 1 is a side elevational view partly in section of a nozzle andholder assembly in accordance with the present invention;

FIG. 2 is an enlarged longitudinal sectional view through the nozzleshowing the internal construction thereof; and

FIG. 3 is a sectional view taken on lines 3-3 of FIG. 2.

Referring now to the drawing, there is shown in FIG. 1 a holder andnozzle assembly in accordance with the pres ent invention. The assembly,as illustrated, comprises an elongated generally cylindrical holder 10and a nozzle 12 mounted at one end of the holder by means of a cap nut14. The terminal end of the holder opposite the nozzle is provided witha port 16 to receive a fitting and a line connecting the assembly to afuel supply source and has an axially extending fuel passage 18 todeliver fuel from the supply source to the nozzle. The holder 10 alsohas an axially extending channel 20 for leakotf fuel which at its upperterminal end communicates with a fitting 22 for connecting the leakoffchannel 20 back to the fuel supply source.

In accordance with the present invention there is provided a compactunitized nozzle assembly which is characterized by novel features ofconstruction and arrangement so that it may be easily assembled anddisassembled to the holder. The nozzle assembly, as best illustrated inFIG. 2, comprises a generally cylindrical body portion and a nozzleshank 32 depending from the lower axial end of the body portion. In thepresent instance, the nozzle shank 32 has a downwardly convergingfrusto-conical section 34 and a generally cylindrical tip portion 36.The frusto-conical section 34 of the nozzle body provides additionalstrength and minimizes distortion. The body portion 30 has an axial bore38 extending inwardly from its inner end which defines a spring chamberC and a lower bore section 40 of smaller cross section within which avalve member 42 is mounted. The valve member 42 has a generallycylindrical main body portion 44, and a tapered downwardly convergingfrusto-conical forward end 46 which terminates in a pointed tip 48. Ifdesired, the valve member 42 may be provided with a double cone seat inlieu of the projected valve seat diameter shown in FIG. 2 to provide amore streamline fiow of fuel past the valve seat. In the presentinstance, the lower bore section 40 is enlarged as at 50 to provide anannular space or fuel chamber 41 for flow of fuel to the nozzle tip andis counter-bored as at 52 to receive a spray tip insert 56 having aninner conical seat 58 against which the tip of the valve element seatsand a plurality of discharge orifices 53 through which fuel isdischarged. The insert 56 has a tapered side Wall generally parallel tothe wall of the forward section 46 of the valve element and spacedtherefrom to define an annular tapered forward section of the fuelchamber 41 adjacent the tip end of the nozzle assembly. The insert 56may be secured in the outer free end of the nozzle shank 32 with anepoxytype sealant and the free end of the nozzle shank 32 may be rollcrimped to secure the tip in place.

An axially extending fuel passage 60 is provided in the nozzle body,which, in the assembled relation, registers with the passage 18, thepassageway 60 having an angled leg portion 62 which communicates withthe fuel chamber 41. The fuel passage 18 in the holder and fuelpassageway 60 in the nozzle are maintained in alignment in the presentinstance by means of a dowel 43 which is press fitted in the holder andhas a clearance fit in the mating hole in the nozzle body 12. It isnoted that by this arrangement, the angular leg 62 of the fuel passagemay be drilled from the nozzle tip end prior to assembly of the tipinsert 56. Accordingly, in the operation of the fuel injection nozzle,fuel from the port 16 passes through the passage 18 through thepassageway 60 and the angular leg 62 into the fuel chamber. Fuelpressure build up against the bias of the spring in the spring chambernow raises the valve element to permit discharge of fuel through theorifices in in the nozzle tip. It is noted that by providing an angledfuel passage and a slightly tapered forward section of the fuel chamber,flow of fuel through the nozzle is laminar, minimizing side thrust onthe valve element to provide a more reliable operation of the nozzleassembly.

A valve actuator assembly normally biasing the valve to a closed portionis mounted in the spring chamber C which, as best illustrated in FIG. 2,includes a compression spring "68 mounted'between' a lower spring seat70and-arrupp'er spring seat 72. The lower spring seat 70 is an annularmember having a circumferential arcuate inner face portion 71 conformingto and engaging the rounded semispherical head 42a at the inner end ofthe valve member. The upper spring seat 72 is also an annular memberhaving a circumferential arcuate inner face portion 73 within which adisc-like valve spring spacer having a ball-like projection seats. Thisarrangement minimizes side thrust on the valve member from the spring68.

The spring 68 is preloaded between the seats by means including a valvelift stop member 76 having a head portion 77 adapted to :be secured tothe nozzle body 30 and a depending rod 78 which is aligned axially withthe valve element and in the closed position of the valve memberhas itslower terminal end spaced from a tapered stem 81 projecting from andformed integrally with the head of the valve to provide a gap G whichdetermines the valve lift. In the present instance, the head 77 of thevalve lift stop 76 is in the form of a bar having a greater length thanthe diameter of the spring chamber C which is adapted to engage in agroove 91 in the upper side wall of the spring chamber to secure theparts of the actuator assembly in place, the groove having a cutaway 93to receive the bar.

The capsulated compact nozzle assembly described above is easy toassemble and may be completely assembled with a preset valve lift gapand spring biasing force prior to assembly to the holder. For example,in manufacturing the assembly, the passageway 60 may be-simply drilledfrom the upper axial end of the nozzle body 30 and the angular leg 62may be drilled from the open front end of the nozzle tip portion.Thereafter, the tip insert 56 may be press fitted in the counterboredopening 52 in the forward end of the nozzle tip and the valve member 42position in the axial bore. The lower spring seat 70 is then positionedover the upper end of the valve element and thereafter, the spring isassembled. The upper spring seat 70 and spacers 80 and 86 are thenpositioned over-theupper end of the spring and then the valve lift stop76 is inserted into the spring chamber With the bar in registry with thecutaway 93. The bar is then depressed to align it with the groove 91 andthen rotated to lock the parts in place. In this position the gap G andspring bias are set. The nozzle is then positioned over the end of theholder and secured thereto by the cap nut. By this arrangement, thenozzle is easy to replace if necessary.

While a particular embodiment of the present invention has beenillustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made therein within thescope of the following claims.

I claim:

1. A capsulated nozzle for a fuel injection nozzle assembly comprising acylindrical body portion an elongated shank of reduced cross sectionprojecting from one axial end of said body portion terminating at itsfree end in a nozzle tip portion having at least one dischargeorificetherein, an enlarged upper axial bore extending inwardly from the axialend face of the nozzle body portion opposite said shank defining aspring chamber, means defining a second lower axial bore coaxiallyof'said springchamber having a lower enlarged portion in the shankdefining a fuel chamber, a valve member mounted in said second axialbore, the nozzle tip having an inner conical seat against which thelower tip of the valve member seats in the closed position, a valveactuator assembly in said spring chamber including a compression springdisposed between an upper and a lower spring seat and a valve lift stopmember for preloading said compress on spring and determining the valvelift, said valve member actuatable upwardly against the bias of saidcompression spring upon build up of fuel pressure in said fuel chamberto permit discharge of fuel through said discharge orifice, said valvelift stop member comprising a transverse bar-like head portion and a roddepending from the head portion confronting the inner end of the valvemember and spaced therefrom in the closed position providing a gapdetermining valve lift, said head portion being of a length greater thanthe diameter of the spring chamber and having an end engageable in agroove in the wall of the spring chamber to secure the elements of theactuator assembly in place, said groove having a cutaway to receive thebar-like head portion.

2. A nozzle as claimed in claim 1 wherein said inner end of the valvemember has a rounded semi-spherical head and the lower spring seat isprovided with a circumferential arcuate inner face portion conforming toand engaging the rounded semi-spherical head of the valve member.

3. A nozzle as claimed in claim 2 including a disc-like spacer betweenthe head portion of the valve lift stop ball-like projection which seatsin a circumferentially extending arcuate face portion of the upperspring seat thereby to minimize side thrust on the valve from thespring.

References Cited UNITED STATES PATENTS 1,759,367 5/1930 Petersen 2395331,811,731 6/1931 Petty 239-533 2,733,960 2/1956 Barfod 239464 2,753,2177/1956 Pecora et al 239-453 3,224,684 12/1965 Roosa 239-533 M. HENSONWOOD, 111., Primary Examiner.

member and the upper spring seat, said spacer having a 15 H. NATTER,Assistant Examiner.

